Darnel is a type of weed that often grows alongside grain crops. It is also known as Lolium temulentum or poison ryegrass. The synonym for darnel is cockle, which is used to refer to any kind of weed that grows with grains. Other synonyms for darnel include ryegrass, wild rye, and bearded darnel. Darnel is often confused with wheat or barley, but it is easily distinguishable by its black seeds and shorter grain stalks. Darnel is famous for its toxic properties, which can lead to dizziness, nausea, and even death if consumed in large quantities.